Absorption refrigeration system



1940- N. 1'. BRANCHE ET AL 2 ABSORPTION REFRIGERATION SYSTEM I I Filed Nov. 26, 1937 2 Sheets-Sheet 1 NELSON 1'. BRANCHEINVlNTbRS ERIC H. RYDEN BERT C. 'SCHICKLER Mud! 1940. N. 'r. BRANCHE ET AL 3 ABSORPTION REFRIGERATION SYSTEM Filed Nov. 26, 1937 2 Sheets-Sheet 2 NELSON 1'. BRANCHE INVENTORS ERIC H RYDEN LBERT c. SCHICKLERI ATTORNEY-S Patented Mar. 12, 1940 UNITED STATES PATENT OFFICE ABSORPTION REFRIGERATION SYS'IEM I tion of Ohio Application November 26, 1937, Serial No. 176,518

14 Claims.

This invention relates to refrigeration systems of the type having an evaporator and means for periodically serving the same with volatile refrigerant, latent heat of evaporation of which serves in transfer of heat from what is-to be cooled. I An object of the invention is to provide novel means for automatically draining from the evaporator at each cycle of operation of thesystem, a small amount of liquid, including such rela tively non-volatile substances as might otherwise accumulate in and impair the efliciency of the evaporator.

The invention is particularly adaptable for the usual absorption refrigeration system wherein the evaporator is served, through suitable connections, by a generator-absorber arranged to operate in alternate heating and cooling stages ammonia and water for example being employed as refrigerant and absorbent respectively, the delivery connection from the generator-absorber to the evaporator including means designed to prevent absorbent. from finding its way to the evaporator while providing delivery of refrigerant thereto in liquid form; such a system being old and well known in the art.

The absorbent being heavier than the re-. frigerant, the invention contemplates drainage from a lower part of the evaporator, so that should any absorbent find its way to the evaporator it will be removed; and the invention contemplates return of the drained liquid to the generator.

The invention employs siphon means for the drainage function, with associated receiver, re-

striction and vent means, so related with each other and with the evaporator that, as important objects of the invention, drainage commences responsive to liquid level within the evaporator and terminates after a predetermined relatively small quantity of theliquid has been removed.

A still more important object, with respect to the generator-absorber, is to provide that the drainage takes place generally at the end of the heating stage and just before start of the cooling stage, so that refrigerant included in the drainage liquid will serve to accelerate the initial absorbing action. More particularly the generator-absorber is preferably provided with an absorption loop into which the drained liquid is introduced to set up circulation by its heat of absorption.

The exact nature of the invention together with further objects and advantages thereof 'will be in connection with the accompanying drawings,

in which Fig. 1 is a conventionalized diagram- -of the evaporator part of such system with a modified form of the invention applied thereto; and Figs. 3 and 4 are end and side elevations of evaporator and associated parts illustrating the invention in another modified form.

With reference now to the drawings and first to Fig. 1 thereof, G is a generator-absorber and E an evaporator, thesebeing the principal units of the system.

The generator has an associated heater H and an absorbing loop 9. There is a delivery connec tion L1 from the top of the generator to the top of the evaporator by way of a trap T, a rectifier R. and a condenser C.

The evaporator E comprises a storage tank E and therebelow the usual heat exchanging or cooling coil e which, it will be understood, ex-

tends within the, chamber to' be cooled. A return line L2 leads from the upper part of ;the evaporator to the sloping up leg of the absorbing loop g of the generator-absorber, r

The system is sealed'closed and contains a volatile refrigerant and an absorbent therefor, such as ammonia and water respectively, in suitable proportion andvolume.

What has thus far been described is old and well-known in the art, and its general operation is cyclic, in two stages, as follows:

Commencing with the absorbed refrigerant in strong solution in the generator-absorber, and the evaporator E substantially empty, heating of the generator by operation of the heater H drives off the refrigerant as a gas. The refrigerant under pressure finds its way to the evaporator E through the trap T and rectifier R which generally prevent passage of absorbent, and the condenser C wherein the refrigerant is liquefied, so that ultimately the evaporator E is largely filled with liquid refrigerant and the generator principally with absorbent only or weak solution. Operation of the heater H is then terminated by'suitable control means not shown and forming no part of this invention, which completes the heating stage of the cycle.

'I'nereupon as the generator-absorber cools, the liquid refrigerant in the evaporator E gasifies and returns to the generator-absorber to be reabsorbed in the absorbent therein, by Way of the line L2 and the loop g of the generator-absorber, the trap T preventing return by way of the line L1. During this stage circulations and evaporation of liquid refrigerant takes place in refrigerant having been evaporated in the evap-' orator and reabsorbed in the generator-absorber,

the cooling stage, and thus the entire refrigeration cycle, has been completed. g

It will be apparent that should any absorbent find its way to the evaporator, being substantially or relatively non-volatile, it'will therein be trapped and accumulate at the bottom, and impair the efficiency of the system and ultimately render it inoperative.

Our invention provides automatic drainage of a small amount of liquid from the'bottom of the evaporator with each cycle, at the latter part of the heating stage and thus just before commencement of the cooling stage, and employs siphon means for the purpose. This siphon means as here shown, includes an "up leg I and a down leg 2 connected to the line L2, preferably with a reservoir chamber 3 between the legs. The up leg I of the siphon has connection with the evaporator by way of a receiver 4. The receiver l has connection with the bottom of the down leg of the evaporator coil e, and this by way of a small opening provided by a restriction 5. The

I receiver 3 is vented effectively to the top of the .follows.

evaporator as by a connection 6 here shown as to a high part of the line L2.

The siphon means and associated parts are so proportioned and arranged that they operate as During the heating stage liquid rises within the evaporator, the connection 6 and the up leg l of the siphon, maintaining substantially the same level in each, residue liquor from the preceding cooling stage, including some liquid refrigerant, finding its way to the receiver 4 and thence into the connection 6 and siphon leg i. As the heating stage nears completion and the evaporator is nearly full, the liquid level rises high enough in the siphon reservoir 3 to overflow into the down leg 2 of the siphon and thus prime the latter and initiate siphonic action. Because of the vent connection 6, this siphonic action is greatly accelerated at the start due to the high liquid in this connection so that the whole system ti, 5, i, 2 is rapidly evacuated even if the lower end of tube 2 is located only slightly below the hollow of the receiver 4. Some flow takes place past the restriction 5 but greatly less than that in the siphon, so that the receiver d and up leg i of the siphon, together with the vent connection ii, are quickly emptied, the siphon broken and drainage terminated. The action is that of quickly draining a small shot of rich liquid from'the bottom of the evaporator.

This shot is delivered by the line L; to the loop 0 of the generator-absorber where, because the shot is of strong solution relative to the weak solution within the absorber, reabsorption instantly commences, and circulation in the loop g is quickly initiated through thermosiphonic action due to heat of absorption. Thus when the cooling stage is commenced, absorption can take place immediately as the required circulation in the absorption loop 9 already is established.

With reference now to Fig. 2, a modified form of the invention is shown as applied to the evap-' leg la.-

The operation of this modification will be generally as before, the draining being accomplished by siphonage at the latter part of the heating cycle, responsive to liquid level in the evaporator part E, drainage being of a limited quantity of liquid determined by the combined volume of the receiver to and the supply leg la, breaking of the siphon being determined by the level of the bottom of this leg.

The advantages of this modification are that of the receiver to has protection by the evaporator part E against heat leakage from the outside, and also gas bubbles formed in the supply connection, are allowed to vent directly upwardly into the evaporator vapor space, eliminating the danger of the siphon being primed during the absorption period due to refrigerant evaporating in this supply leg.

With reference now to the modification of Figs. 3 and 4, the arrangement is generally similar to that of Fig. 2 but the receiver ib is located wholly within the storage part E of the evaporator, and its supply connection Hlb located within the down leg part c of the evaporator cooling coil e.

To position the lower end of the connection Hlb a partition II is arranged thereabout, fitting within the surroundingcooling coil leg e, the latter extending downwardly below the cooling coil branches indicated. To provide restricted inlet to the connection lilb it is perforated as at 51) above the partition ll. Thus a sump is formed below the opening 5b and particularly below the partition H, in which solid foreign particles will be permanently trapped.

A vent 6b is provided above the supply connection lllb, a siphon supply leg lb, and the down leg 21) of the siphon leads-to the line L2, all as before. The lower edge of the dome which provides the supply leg lb is sloping as indicated, to accurately and conveniently position the dome in the receiver ib.

phon supply leg tending to raise the level therein above the top of the down leg of the siphon which would cause loss of refrigerant.

What we claim is:

1. In a refrigeration system having an evaporator, and refrigerant-serving means therefor including a generator-absorber arranged to operate in alternate heating and cooling stages: siphon means arranged to provide drainage from a low part of said evaporator commencing responsive to liquid level therein, and having vent means to the top of said evaporator and a cooperative restriction therebelow, for terminating said drainage.

2. In a refrigeration system having an evaporator, and refrigerant-serving means therefor including a generator-absorber arranged to operate in alternate heating and cooling stages: a receiver having restricted communication with a low part of said evaporator and vent communication with a high part of said evaporator, and siphon means arranged to empty said receiver responsive to liquid level in said evaporator.

3. In a refrigeration system having an evaporator with interconnected upper storage and lower heat 'exchanger parts, and refrigerantserving means for said evaporator including a generator-absorber arranged to operate in alternate heating and cooling stages: a receiver having restricted connection with said evaporator heat exchanger part and vent connection with said evaporator storage part, and siphon'means arranged to empty said receiver responsive to liquid level in said evaporator storage part.

4. In a refrigeration system having an evaporator with interconnected upper storage and lower heat exchanger parts, and refrigerantserving means for said evaporator including .a generator-absorber arranged to operate in alternate heating and cooling stages: a receiver hav-' ing restricted connection with said evaporator heat exchanger part and vent connection with said evaporator storage part, and siphon means arranged to empty said receiver responsive to liquid level in said evaporator storage part, said receiver being located adjacent said evaporator storage part. r i

5. In a refrigeration system having an evaporator with interconnected upper storage and lower heat exchanger parts, and refrigerantserving means for said evaporator including a generator-absorber arranged to operate in alternate heating and cooling stages: a receiver having restricted connection with said evaporator heat exchanger part and vent connection with said evaporator storage part, and siphon means arranged to empty said receiver responsive to liquid level in said evaporator storage part, said receiver being located within said evaporator storage part.

6: In a refrigeration system having an evaporator with interconnected upper storage and lower heat exchanger parts, and refrigerant-serv- I ing means for said evaporator including a generator-absorber arranged to operate in alternate heating and cooling stages: a receiver having restricted connection with said evaporator heat exchanger part and vent connection with said evaporator storage part, and siphon means arranged to empty said receiver responsive to liquid level in said evaporator storage part, said receiver being located within said evaporator storage part and its said restricted connection being located within said evaporator.

7. In a refrigeration system having an evaporator with interconnected upper storage and lower heat exchanger parts, and refrigerantserving means for said evaporator including a generator-absorber arranged to operate in alternate heating and cooling stages: a receiver having restricted connection with said evaporator heat exchanger part and vent connection with said evaporator storage part, and siphon means arranged to empty said receiver responsive to liquid level in said evaporator storage part, said orator with interconnected upper storage and.

lower heat exchanger parts, and refrigerantserving means for said evaporator including agenerator-absorber arranged to operate in alternate heating and cooling stages: a receiver having restricted connection with said evaporator heat exchanger part and vent connection with said evaporator storage part, and siphon means arranged to empty said receiver responsive to liquid level in said evaporator storage part, said receiver being located within said evaporator storage part and its said restricted connection being located principally within a leg of said evaporator heat exchanger part.

: 9. In a refrigeration system having an evaporator with interconnected upper storage and lower heat exchanger parts, and refrigerantserving means for said evaporator includinga generator-absorber arranged to operate in alternate heating and cooling stages: a receiver hav-' ing restricted connection with said evapoator heat exchanger part and vent connection with said evaporator storage part, and siphon means arranged to empty. said receiver responsive to liquid level'in said evaporator storage part, said receiver being located withinsaid evaporator storage part heat exchanger part.

10. Ina refrigeration system having an evaporator with interconnected upper storage and lower heat exchanger parts, and refrigerant-serving means'for said evaporator including a generator-absorber arranged to operate in alternate heating and cooling stages: a receiver having restricted connection with said evaporator heat exchanger .part and vent connection with said evaporator storage part, and siphon means arranged to empty said receiver responsive to liquid level in said evaporator storage part, said receiver being located within said evaporator storage part and its said restricted connection being located principally within said evaporator heat exchanger part, said vent connection beinglocated over said restricted. connection. v

11. In a refrigeration system having an evaporator with interconnected upper storage and lower heat exchanger parts, and refrigerant-serving means for said evaporator including a'generatorabsorber arranged to operate in alternate heating and cooling stages: a receiver having restricted connection with said evaporator heat exchanger part and vent connection with said evaporator storage part, and siphon means arranged to empty said receiver responsive to liquid level in said evaporator storage part, said receiver being located within said evaporator storage part and its said restricted connection being located principally within a leg of said evaporator heat exchanger part, said leg being .arranged to provide a sump at its lower extremity. 12. In a'refrigeration system having an evapo rator with interconnected upper storage and lower heat exchanger parts, and refrigerantserving means for said evaporator including a generator-absorber arranged to operate in alternate heating and cooling stages: a receiver having restricted connection with said evaporator heat exchanger part and vent connectionwith said evaporator storage part, and siphonmeans and its said restricted connection being located principally within a down leg of said evaporator rator with interconnected upper storage and lower heat exchanger parts, and refrigerant-serving means for said evaporator including a genexchanger part, and partition 'means positioning said restricted connection in said leg.

14. In a refrigeration system having an evaporator with interconnected upper storage and lower heat exchanger parts, and refrigerant-serving tition means.

means for said evaporator including a generatorabsorber arranged to operate in alternate heating and cooling stages: a receiver having restricted connection with said evaporator heat exchanger part and vent connection with said evaporator storage part, and siphon means arranged to empty said receiver responsive to liquid level in said evaporator storage part, said receiver being located within said evaporator storage part and its said restricted connection being located principally within aleg of said evaporator heat exchanger part, and partition means positioning said restricted connection in said leg, said restricted connection having a lateral opening above said par- NELSON T. BRANCHE. ERIC H. RYDEN. ALBERT C. SCHICKLER. 

